In addition, it fits with Amazon's Kindle, the electronic reader tool that allows subscribers access to 90,000 newspapers, magazines, books and blogs. Audible books are already compatible with Kindle, although they have to be sideloaded from a PC rather than downloading wirelessly, according to The Guardian.

"Audible.com offers the best customer experience, the widest content selection and the broadest device compatibility in the industry. Working together, we can introduce more innovations and bring this format to an even wider audience," said Amazon's senior vice president for worldwide digital media.

According to MarketWatch, the deal also includes purchasing Audible's cash and short-term investments at closing. Shares of Amazon.com increased 26 cents to close at US$74.21 on Wednesday.